The present invention relates to agricultural harvesters and, more particularly, to axial flow combine harvesters having a threshing and separating unit with at least one generally longitudinally arranged rotor for advancing crop material along a generally helical path. In particular it relates to the discharge means provided adjacent the discharge end of the threshing and separating unit.
In axial flow combines the harvested crop is threshed and separated as it is conveyed between a longitudinally arranged rotor and the inner surface of an associated chamber comprising threshing and separating concaves. The straw is conveyed along a helical path along the inner surface of the chamber until it reaches the end thereof. Commonly, the chamber ends before the outlet of the combine and the paddles mounted to the rear end of the rotor throw the straw downwardly, in the direction of the sieves of the cleaning system.
In order to prevent the accumulation of straw on the upper sieve, the threshing and separating system usually is provided with a beater rotor to which the threshed straw is fed via a guide plate and which ejects the straw through the outlet of a rear hood onto the field. Such structure is described in U.S. Pat. Nos. 3,669,122 and 3,916,912.
However, most of the straw which is released by the rotor and the chamber tends to concentrate at one side of the combine harvester, i.e. near the side where the helical flow path reaches the end of the chamber and the crop starts following a straight, downward trajectory.
When the crop starts accumulating on the guide plate to the beater, its rearward flow may be hampered and the area between the chamber outlet and the beater may quickly get plugged. Finally the crop flow through the chamber itself is halted and the threshing and separator rotor will get stuck, unless the operator takes immediate action and clears the plugged rear area.
Accordingly there is a need for a means that reduces the chances that crop material starts accumulating in the area above the guide plate to the beater.
According to the present invention, there is provided a combine harvester comprising:
a main frame;
a threshing and separating arrangement mounted to said main frame and including:
a generally cylindrical chamber having a generally longitudinal axis and comprising a separating concave assembly; and
a rotor assembly mounted for rotation in said chamber and comprising a generally cylindrical rotor body with a separating section associated with said separating concave assembly; and
a beater assembly arranged behind said concave assembly for receiving threshed and separated crop material therefrom and projecting it rearwardly, said beater assembly comprising a transverse guide means mounted behind said separating concave assembly and below said rotor body, and a transverse beater rotor;
characterised in that said chamber comprises a curved guide plate arranged behind said separating concave assembly and above said guide means for distributing the separated crop material over the full width of said guide means.
The curved guide plate minimizes the chances that material starts accumulating in the one or other corner and the full separating system gets plugged.
Preferably the guide plate has an outlet edge which is oriented in a direction which is generally transverse to the direction of the crop flow. So the edge intersects the helical flow at an angle. In a preferred embodiment, the curved guide plate has a generally triangular shape with its base adjacent the separating concave and the tip adjacent the rear end of the chamber. The guide plate may have an upper edge extending at the level of the axis of the cylindrical chamber.
This arrangement provides for a simple yet effective flow spreading dividing structure. It may be used advantageously in a harvester having a pair of juxtaposed cylindrical chambers. Then the guide plates for each chamber may be linked together to form one guide element providing two guide surfaces.
The guide element may be used in combination with a threshing and separator rotor having adjacent its rear end a plurality of generally longitudinally arranged paddles for assisting in discharging the crop. The rotor further may be provided with a plurality of longitudinal elements having a leading, generally longitudinally arranged crop engaging face, and a plurality of transverse elements having a generally transversely arranged crop engaging edge.